We hear of Basil everywhere these days. Though based in Baker Street, Disney's Great Mouse Detective certainly gets around. Below is a report of various sightings of characters from Disney's The Great Mouse Detective in other films, television series, and anywhere else they may have been spotted.

The official Disney website
You used to find this image if you searched the Disney Archives

Baker Street Journal
The comic strip column "Art In the Blood" by Scott Bond gave us this Basil in an unknown issue

Disney's House of Mouse, 2001-2
Check out these episodes:Rent Day: Ratigan Ratatouille is featured on the menuDonald's Lamp Trade: Basil, Dawson, and Ratigan visit the famous clubThe Mouse Who Came to Dinner: Ratigan again appears on the villains' tableHouse of Scrooge: Ratigan is in the soup lineDonald Wants to Fly: Basil and Dawson are seen in the ad for Dumbo Airlines

Disney.com House of Mouse website
One of the video clips featured Basil

Grosvenor Resort, Orlando, FL, 2002
A tribute to The Great Mouse Detective featured standees of the characters

Disney Club, 2002
Basil and friends appeared in the membership binder and online on the search results page

Battle for Procyon, Treasure Planet PC game, 2002
One of the crew members was named Olivia Flaversham

Fantasia/2000 video
The introduction by Roy Disney mentioned the use of computer animation in GMD

Lion King Special Edition DVD, 2003
Disc 2, Film: Origins

World of Disney store, Downtown Disney
The montage video that ran in the former Wonderland Room showed several clips from The Great Mouse Detective

Jungle Book 2-disc DVD, 2007
The featurette on the making of the film showed Vance Gerry standing in front of the storyboards for Great Mouse Detective

Walt Disney Company Annual Report, 1993
Basil and Toby were depicted in a cover montage

Disney Wall Calendar, 1998-99
Perhaps the only wall calendar ever to include a scene from Great Mouse Detective, though a British 1994/1995 department store premium calendar contains a shot of the video cover and the 2013 calendar from D23, From Concept to Classic, includes a piece of pre-production art.

Walt Disney Page-A-Day Desk Calendar, 2003
Although this calendar depicts scenes from GMD every year, Olivia once appeared on the box

Advent Calendar, 1998
Basil was among a huge host of characters, and was seen inside the door for December 15th

Tales from the Laughing Place magazine #13, 2009
Contained an article on animation maquettes, including Ratigan

Souvenir map from Disneyland
Basil and Dawson were among the many characters around the map border

Music video featuring French pop star Douchka Esposito, 1986
Although Whatsits Galore can not recommend the music, Basil and Ratigan do appear in the video

Disney Rewards Villain quiz
Disney credit card holders can take this quiz to find their inner villain. Although Ratigan is not one of the choices, there are some stills from The Great Mouse Detective along the way

Original Movie Ticket
Those luckey few invited to the premiere of The Great Mouse Detective received a special ticket.